Work clamping device



Dec. 25, 1951 L. l. KAPLAN ETAL WORK CLAMPING DEVICE Filed NOV. l, 1948 5 Sheets-Sheet 1 l l 5*- l ,l

F n L el d 7o l 2| l Dec. 25, 1951 L 1 KAPLAN ETAL 2,579,675

WORK CLAMPING DEVICE Filed Nov. l, 1948 5 Sheets-Sheet 2 '4 Ill W *l I Y NVENToR.

0 J KAPzA/v 6057A v l/cw A25/s ,4 frog/vnf:

Dec. 25, 1951 L l, KAPLAN ETAL v 2,579,675

WORK CLAMPING DEVICE l Filed Nov. l, 1948 5 Sheets-Sheet .'5

` INVENToR. 0 JT /fAAcA/v @im mju/M2 Dec. 25, 195] 1 KAPLAN ET AL 2,579,675

WORK CLAMPING DEVICE Filed Nov. l. 1948 V5 Sheets-Sheet 4 @wmvw Dec. 25, 1951 L. l. KAPLAN ETAL 2,579,675

WORK CLAMPING DEVICE Filed Nov. 1, 1948 5 sheets-sheet 5 EME- ll Patented Dec. 25, 1951 WORK CLAMPING DEVICE Leo I. Kaplan, Detroit, and Gustav von Reis, Grosse Pointe, Mich., assignors to Detroit Broach Company, Detroit, Mich., a corporation of Michigan Application November 1, 1948, Serial No. 57,634

This invention relates generally to work holding equipment, and refers more particularly to improvements in xtures of the type employed to clamp work pieces in place while being processed.

One of the objects of this invention is to provide a relatively simple inexpensive fixture ca' pable of being rapidly operated with ease and designed to hold a work piece firmly so that it will withstand cutting stresses of considerable proportions without working loose.

Another feature of this invention is to provide a work clamping fixture designed to securely hold the work during the cutting operation, so that the desired tolerances can be maintained and to accomplish this result without distorting the work.

Still another object of the invention is to provide a work clamping fixture having a swinging arm successively movable to work clamping and releasing positions in response to movement of a cam slide in either of two directions. This arrangement minimizes lost motion and enables the xture to be used where high production is required.

A further feature of this invention is to provide a xture of the above general type having a plurality of work clamping members successively movable as a unit to work clamping and work releasing positions in response to movement of the cam slide in each of the two directions of movement thereof.

` The foregoing as well as other objects will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawings, wherein:

' Figure 1 is a semi-diagrammatic front elevational view showing a work clamping xture constructed in accordance with this invention and applied to a typical double slide broaching machine;

Figure 2 is a semi-diagrammatic side elevational view of the construction shown in Figure l Figure 3 is a sectional view taken on the ,plane indicated by the line 3--3 of Figure 1;

M Figure 4 is a sectional view taken on the plane indicated by the line 4-4 of Figure 3;

Figure 5 is a sectional view taken on the line 5-5 of Figure 3;

Figure 6 is a sectional view taken on the line 6-6 of Figure 2;

Figure 7 is a sectional view taken on the line I--T of Figure 3;

Figure 8 is a sectional view taken on the line 8-8 of Figure 3;

I Figure 9 is a sectional view taken on the line 9-9 of Figure l;

6 Claims. (Cl. 90-33) Figure 10 is a sectional view taken on the line IIJ-I 0 of Figure 9; and

Figure l1 is a semi-diagrammatic fragmentary perspective view of a part of the construction shown in Figure l.

Although the work holding fixture forming the subject matter of this invention is not limited in its use to any specific type of machine, nevertheless, it finds particular utility when employed in connection with multiple slide type broaching machines. Accordingly, for the purpose of illustrating this invention, the work holding xture is shown as installed on a typical double slide type broaching machine.

Such a machine is shown diagrammatically in the several iigures of the drawings, and. comprises generally a pair of laterally spaced vertical slides I2 and I3 respectively supporting suitable tools in the form of broaches I4 and I5. A table I6 is supported at the front side of the machine, and is suitably fashioned to respectively support a pair of horizontal slides I'I and IB.

Any suitable power mechanism, such for example, as hydraulic rams are provided for reciprocating the vertical slides, and the latter are operated in out-of-phase relationship, so that while one of the tools is moved downwardly on its cutting stroke, the other tool is retracted or moved upwardly to position the tool for the next cutting operation. In Figure l1 of the drawings, the tool or broach I4 is shown in a cutting position and the tool I5 is shown in a position on its retracting stroke. The horizontal slides may also be operated by suitable hydraulic rams arranged to move these slides in such timed relation to movement of the Vertical slides that when one of the tools orV broaches is on its cutting stroke, the adjacent horizontal slide is positioned in operative relation to this tool and the other horizontal slide is located. in its rearwardmost or retracted position with respect to the tool adjacent this slide. Referring again to Figure 11 of the drawings, it will be noted that the slide I1 is positioned inoperative relation to the tool I4 and the slide I8 is located in its retracted position with respect to the tool I5. The specific means for operating the respective slides in the above timed relationship is not shown herein and may be any one of the Iaccepted types employed on orthodox double slide broaching machines.

The specific contours of the tools or broaches i4 and I5 depend on the type of work to be processed. lfn the present instance the tool I4 has a cross sectional contour fashioned to machine a connecting rod bearing cap I9, and the tool I5 is contoured to sever the cap from a forged connecting rod indicated in Figure 9 by the reference character 29.

With the above in view, reference is now made more in detail to the work clamping ixture forming the subject matter of this invention. This xture is shown in the several igures of the drawings as comprising a vertical slide 2l, a pair of work clamping arms 22, 23 and a pair of work holding members 25, I5. In this connection it will be noted that the vertical slide 2| is actually formed integral with the tool slide "I2 and vextends for substantially the full length or the latter.

The arms 22 and 23 are respectively supported above the work molders 24. and 25 at the front side of the tools or broaches for swinging movel ment in laterally spaced substantiallyA parallel vertical planes. In detail the work clamping arms are carried by a bridge or rigid support 25 which extends transversely of the tool slides at the front sides of the tools and is attached at opposite ends to the vertical frame of the machine by suitable brackets 21. The upper ends of the work clamping arms are respectively pivoted to the support 25 by a bar 29. As shown particularly in Figure 3 of the drawings, a pad 30 of Wear resisting material is removably secured to the swinging or lower end of each arm by a stud 3|. As will be more fully hereinafter set forth, the pads 3!! are positioned on the swinging ends of the arms to engage the work to be clamped on the respective work holders.

In the present instance, the work holder 24 is Xed on the slide I'I and is formed with a recess 32 in the top face adjacent the inner side thereof. This recess is of suiiicient dimension to receive a bearing cap I9, and as shown in Figure 8 of the drawings, is formed with shoulders 33 at opposite side edges for engaging the usual flanges on the cap I9 to locate the latter in a position where the cutting portion of the broach I4 may lpass downwardly through the cap and machine Vthe inner surface thereof. In this connection attention is again directed to Figure 3 of 'the drawings wherein it will be noted that the inner face ofthe work holder 24 is fashioned with a recess S4 extending downwardly from the base of the recess 32 to the bottom of the work holder and positioned to provide ample clearanceV for the broach .I 4.

V'The work or bearing cap I9 is held in rm contact with the base of the recess 32 during the broaching operation by the arm 22. The arm 22 is shown in Figure 3 of the drawings in its work Vclamping position wherein thewear-resisting pad 35 securely engages the top of the work I9, and holds the latter against displacement relative to the holder 24 Aas the breach I4 is moved downwardly to effect the machining operation. 'Ihe swinging end of the arm 22 is formed with a. recess 35 aligned with the recess 24 .and of sufficient dimension to provide ample clearance for the passage .of the broach I4.

The work holder 25 is formed with ya recess 36 in the 'top face thereof and a'pin 31 extends upwardly from the base of the recess 3S. As shown in Figure 9 4of the drawings, the pin is adapted to engage in the opening provided at the wrist pin end of the connecting rod 25, and the recess 35 is of sufcient dimension to accommodate the connecting rod. It will be understood that the connecting rod '2li is in the form of a forging having the bearing cap I Q integral therewith, and that the bearing cap rests on the baseV oi the recess at the .inner end of the .holder 25.

Cil

Referring now to Figure 10 of the drawings, it

will be noted that the base portion of the recess 36 extends beyond the inner end of the holder and is formed with slots 33 at opposite sides of suilicient dimension to provide ample clearance for the passage of the tool I5.

The above arrangement is suchthat when the holder 25 is in its forwardmost position relative to the tool I5, the slots 38 respectively register with the path of travel of the laterally spaced setsV of teeth im projecting inwardly from the broach I5. It will be understood that the pin V3l positions the connecting rod forging 25 on the base of the recess 35 to enable the teeth 4U on the broach'-I5 to sever the cap section IS from the remaining part of the rod when the holder is located in its operativeor forwardmost position. During the above operation the cap end of the connecting rod forging is rmly held against the base of the recess 35 by the arm 23. In Figure 9 of the drawings the arm 23 is shown in a position wherein the wear resisting pad 3l) is Ain clamping contact with the work, and it will be noted from Figure 10 of the drawings that the width of the pad 3! is less than the lateral spacing between the broach teeth 55, so as not to interfere with movement of the tool I5. Y Y

The work holder 21's is secured to the slide I'I for movement as a unit with the latter, and the operation of the slide I'i is so timed with the operation of the slide I2 or broach I4 that when the latter is in its uppermost position, the slide I'I is in its forwardmost position. When in this latter position, the slide positions the work holder 24 with the Work I9 in the path of travel of the broach I4, so that the surface of the work is machined as the broach I4 is moved downwardly.

As indicated above the total I5 operates in outof-phase relationship to the tool I4, so that when the tool I4 is in its uppermost position, the tool I5 is in its lowermost position. Thework holder 25 is secured to the slide I6, and the operation of the latter is so timed with respect to the movement of the tool I5 that when the lattter is in its inoperative or'lowermost position, the slide or tool holder 25 is in its retracted out outermost position. The arrangement is such that the slide I8, together with the work holder 25, is moved inwardlyin timed relation to upward movement of the tool I5 to its operative position, so that the work 20 is aligned with the tool I5 when the latter is again moved downwardly. As the toolY I 5 is returned to its operative or uppermost position, the tool I4 performs its cut on the work I9 and upon completion of this cut, the slide I'I together with the work holder 24 Ais retracted. Thus it will be noted that one `of the tool holders may be unloaded and reloaded during the interval the work in the other tool holder is being processed, and as a consequence, substantially continuous operation results. n

It follows from the foregoing that the arms 22 and 23 must be .swung to their work clamping positions upon movement of either tool on its operative stroke, and these arms must Vbe moved to their work releasing positions upon completion of the operative stroke of either tool. With this in view, reference is again made to .Figure 3 of the drawings, vwherein it will be noted that the two arms are simultaneously operated by a member 4l mounted on the bottom surface of themember 4I is substantially T-shaped in cross 'Seca Referring totion, and a pair of gibs 42 are respectively secured to the bottom surface ofthe bridge 26 at opposite sides of the member 4| and cooperatev with the flanges on the latter to guide the same. In any event the bottom surface 43 of the member 42 is tapered and engages the adjacent top Surface of the bar 26. The direction of taper is such that movement of the member 4| outwardly applies a cam action on the bar 29 to swing the lower ends or pads 30 on the arms to their respective work clamping positions. On the other hand, movement of the member 4| in an inward direction releases the bar 29 and permits the arms to be swung to their work releasing positions. The extent of movement of the arms between the two above mentioned positions is limited by pins 44 which respectively extend through enlarged openings 45 formed in the arms and have the opposite ends engaging the bridge or support 25.

The member 4| is operated by a rock arm 41 r pivotally mounted intermediate its ends on a pin 48 for swinging movement. In the present instance the pin 48 is mounted on the support or bridge 26 with its axis extending parallel to the aligned axes of the pins 2li, so that the arm 41 rocks in a plane parallel to the planes of the respective arms 22 and 23. The rock arm 41 is connected to the member 4| at a point between the pin 48 and the lower end of the rock arm by a stud 49. The head of the stud is pivoted to the rock arm 41 by a pin 59, and the shank oi the stud extends axially through the member 4|. Suitable stop nuts 52 are threaded on the stud beyond the outerend of the member 4|, and the latter is urged into engagement with the stop The coil spring 53 surnuts bya coil spring 53. rounds the stud between the inner end of the member 4| and the head of the stud. Actually the coil spring 53 normally urges the tapered or cam face 43 on the member 4| into wedging engagement with the bar 29 and thereby yieldably urges the pads 39 on the work clamping arms into engagement with the work. With this arrangement variations in the dimension of the work may be compensated for without interfering with the clamping action.

Referring again to Figure 3 of the drawings. it will be noted that the rock arm 41 is normally urged in a clockwise direction about the pin 48 to locate the member 4| in its clamping position by a spring pressed plunger assembly 54. The assembly 54 comprises a casing 5,5 and a plunger 56 slidably mounted in the casing. The inner end portion of the plunger is reduced and extends through the adjacent end of the casing for engagement with the upper end of the rock arm 41. A suitable coil spring 51 is supported in the casing between the outer end of the plunger and adjacent end of the casing for urging the plunger in a direction to swing the rock arm in a clockwise direction about the pin 48.

The rock arm 41 is operated in timed relation to 'movement of the tool slides |2 and i3 by cams mounted on the slide '2 I. In the present instance three cams |50, 6| and |52 are suitably secured to the slide 2| for operating the work clamping arms through the rock arm 41. The cam 50 may be considered as the operating cam. and the cams 6| and 52 the releasing cams. The operating cam Eil is in the forni' of a bar elongated in the direction of movement of the slide 2| and secured to the front face of the slide. The lower end of the cam il is formed with a cam face 63 adapted to engage a roller B4 on the lower end of the rock arm to positively swing the rock arm in a ating member 4| in an outward direction. As the operating member 4| moves outwardly, the cam face 43 cooperates with the bar 29 to swing the arms 22 and 23 to their work clamping positions. The location of the cam face B3 is such that it engages the roller 54 when one of the work holders is in its operative position and when the other work holder is retracted.

The cam 60 is provided with a straight edge 64 extending upwardly from the cam face 63 in parallel relation to the slide 2| to maintain the work clamping arms in their operative position for a predetermined length of time, depending on the length of the edge 64. This length is, of course, suicient to maintain the work clamping arms in their operative positions throughout the full cutting stroke of the tools.

The releasing cam 6| is secured to the slide above the upper end of the cam 60 in a position to engage the upper end of the rock arm 41 and swing the latter in a counterclockwise direction against the action of the spring 51 to release the member 4| from the bar 29 and thereby release the work clamping arms. The space between the cam 6| and the upper end of the cam 6|) is such that the former is not engaged with the rock arm until the roller B5 reaches the upper end of the straight edge 64 on the cam G9. As shown in Figure 5 of the drawings, a pair of rollers 56 are respectively supported at opposite sides of the upper end of the rock arm on a pin 61,

, and the releasing cam 6| is adapted to engage these rollers.

Thus from the foregoing it will be noted that as the cam slide 2| moves downwardly with the tool slide I2, the cam face 63 on the cam 6U engages the roller 55 and swings the rock arm 41 in a clockwise direction to move both the work clamping arms to their operative positions by the member 4|. Although both arms 2'2 and 23 are moved to their work clamping positions, neverthe1ess,' the work holder 24 is the only one in position to cooperate with the arm 22 to clamp a work piece in position for engagement by the tool |4. The other work holder 25 is retracted and does not interfere with movement of the arm 23 to its work clamping position.

The work clamping arms are maintained in their operative positions throughout a downward length of travel of the tool slide I 2 corresponding machining operation performed by the tool I4,

the releasing ycam 6| engages the rollers 66 on the upper end oi the rock arm 41 to release the work clamping arms.

When the work clamping arms are released from their operative positions, the work` holder 24 is retracted, and the work holder 25 is advanced to a position in operative relation to the tool |5 which has previously been returned to itsuppermost position. As the tool l5 is lowered to process the work on the holder 25, the tool slide |2 together with the cam slide 2|, is moved upwardly and the work clamping arms are again swung to their operative positions. In this connection reference is again made to Figure 3 of the drawings wherein it will be noted that the upper end of the cam 69 is formed with a cam face 10 similar to the cam face 63 in that it engages the roller 65 on the lower end of the rock arm 61 and swings the latter in a clockwise direction to cause the member 4| to again engage the bar 29 on Athe arms 22 and 23.

operative .position by 4the straight edge 64 on-the cam lluntil the tool I5 completes its cut. When the tool l5 reaches the end of its cutting stroke, the roller 65 is released from the cam .E9 and the rollers .BS areengaged by the cam .$2 to swing the arm 61 in a counterclockwise direction to release the clamping pressure applied by the member 4l In detail the releasing Cam 62 comprises complementary sections secured to the slide 21 at opposite sides of the cam 60 Aimpositions to engage both the rollers 36 `and therebyrswing `the rock arm in a direction Yto again release the work clamping arms from their operative positions. As indicated above the releasing cam 6i! is so vpositioned on the slide that it engages the rollers 66 subsequent' to the cutting operation of the tool l5 and as the lroller 65 leaves the straight portion 54 of the cam E59.

4It follows from the `foregoing that the Xture is thoroughly automatic in operation and is especially Aadaptable to breaching or equivalent machines, wherein a plurality of tools are ,altere nately moved throughout their cutting strokes, and wherein one tool lholder is in its operative position while the other is in its retracted position where it may be reloaded while the work in the rst tool holder is being processed.

What'we claim as our invention is:

1. AIn a breaching machine including a pair of parallelly arranged alternately operating broach carriers, and a work support for each broach carrier adapted to present the work in operative relation thereto during the working stroke thereof kand withdraw it during the return stroke; work.

clamping means comprising Va rockable member provided with a pair of arms for respectively clamping the work on lsaid supports when eachv is Vin operative position, and cam means movable with one of said broach carriersV for actuating said :rockable member on -both the working and return strokes thereof, the one operation `clamping the work while roperated upon by the broach of the said one of said carriers and vthe other clamping the work vwhen operated upon by the Ybroach of the other carrier.

2. The construction as in claim 1 having a support extending transversely -to the direction omovementof said rvcarriers and spaced rinfront thereof, -rto which said .support said rockable member iis lpivoted, fa :lever .also pivoted on lsa-itl support actuated by .said cam means, randa cam carried by said lever engaging said rockabl'e member to :depressthe same during -Tthe working stroke `of each broach. Y

.3. :The construction vas in :claim 2 having the yrockable member :pivoted on the front 'side-of said ,support and inclining -downward towards said :broach carriers and havingthe arms thereof connected .by -a rod beneath vsaid support, v'the cam carried by said lever extending between the bottom of `said ,support and vsaid rod to simultaneously `depress both arms when 'the lever is rocked 1 and engage :the Ywork :alternately thereb in successive operations. Y

v4. The construction as 'in vclaim 3 having lthe lever fulcrumed intermediate its ends, lone endiof said lever engaging said cam means to operate said rockable member in a downward direction and -the other end engaging said cam means to release downward pressure on said rocha-ble member.

5. The construction as in claim 4 in which rollers are mounted on the opposite ends of lthe leverand said cam means 'has a portion thereof for engaging a roller actuating the lever to clamp the work, and a portion engaging the opposite roller for releasing clamping pressure on the work.

6. VThe construction as in claim 5 having a resiliently yieldable element intermediate rsaid lever andthe cam carried thereby permitting .of clamping work pieces varying in thickness.

LEO I. GUSTAV voN REIS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED VSTATES APATENTS Number Name Date 1,642,593 Perkins `et al. Sept. 13, `1927 1,696,392 Eggenweiler et al. Dec. `25, 1928 1,938,233 Vallone et al Dec. '5, 1933 `2,507,581 

